[issue40170] [C API] Make PyTypeObject structure an opaque structure in the public C API

[hai shi]

Change by hai shi <shihai1991 at 126.com>:


----------
pull_requests: +18889
pull_request: https://github.com/python/cpython/pull/19541

_______________________________________
Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue40170>
_______________________________________